Method and device for shaping a wave winding

Abstract

A method is used to shape a wave winding by way of a flat former (10; 110) able to be rotated about its longitudinal axis, wherein a plurality of parallel wires (14) are fed in perpendicular to the axis of rotation of the former (10; 110) by way of a wire infeed (16), wherein the wires (14) are wound alternately around the former (10; 110) by rotating said former in steps and are shaped into a wave winding (100) by virtue of lateral offsetting, carried out between said stepped rotation, relative to the wires (14) already located on the former, wherein, when the wires (14) are wound, the wire infeed (16) follows the wires as far as into the region of the former (10). To be able to produce a wave winding that is less tensioned and is therefore able to be better further processed, it is proposed for the former (10), when the wires (14) are wound, to first be rotated by less than 180 degrees, for the winding heads (20) that have just been partially shaped to be reshaped in an intermediate step by way of shaping jaws (24, 26; 124, 126), then for the wire infeed (16) to be withdrawn from the region of the former (10), and finally for the former (10) to be rotated on to 180 degrees for the final shaping of the winding heads (20).

Description

[0001] Method and device for forming a wave winding

[0002] According to the preamble, the invention relates to a method for forming a wave winding using a flat template rotatable about its longitudinal axis. A plurality of parallel wires are fed perpendicular to the template's rotation axis by means of a wire feed. The wires are alternately wound around the template by gradually rotating it by 180 degrees and formed into a wave winding by lateral displacement relative to the already wound wires. During winding of the wires, the wire feed follows the wires into the region of the template. The present invention also relates to a device having the features of the preamble of claim 7.

[0003] Such a method with an associated device is known, for example, from DE 102015 120661 A1. It has been shown that problems can arise during implementation of the method because the wire feed extends into the area of ​​the template during winding. The winding process therefore cannot be carried out to the ideal of a step-by-step rotation of the template by 180 degrees, but must be aborted at an intermediate stage of less than 180 degrees. The incompletely bent winding heads result in tensions in the wires, which accumulate as the winding progresses and complicate subsequent processing, since the wave winding must be transferred into stator slots in intermediate steps, possibly with the aid of tools with slots.

[0004] The object of the present invention is to enable a better shaping of the winding heads already during the manufacturing process of the wave winding,

[0005] According to the invention, the object is achieved by one of the methods mentioned at the outset, in which the template is initially rotated by less than 180 degrees during winding of the wires, in an intermediate step the just partially formed winding heads are reshaped using forming jaws, subsequently the wire feed is withdrawn from the area of ​​the template and finally the template is rotated a further 180 degrees for the final forming of the winding heads. The solution according to the invention offers the advantage that the wires are fixed and optionally reshaped in a position in which the template has not yet been rotated a full 180 degrees. This angular position corresponds to the maximum achievable to date at which the wire feed, which is necessary to stabilize the wires during the bending process, would collide with the rotating template if it were to rotate further.The post-forming process then bends the wires to a 180-degree angle or more relative to the half of the winding head located on the underside of the template. The heads are therefore fully formed, preventing stress from building up during winding due to incomplete bending.

[0006] After removing the wire feed, the template can be rotated further to the final position up to 180 degrees before a shaping step follows in the axial direction with respect to the longitudinal extension of the template.

[0007] In a preferred embodiment of the method, the forming jaws remain closed until the wire feed is removed. This prevents frictional forces acting on the wires from the wire feed from causing undesirable deformation of the winding heads.

[0008] In order to prevent the forming jaws from hindering the winding process itself, it is intended that the forming jaws are only brought into contact with the wires for the duration of the forming process.

[0009] In a particularly preferred further embodiment of the method, it is provided that the reshaping is carried out by means of a one-sided or two congruent, bilateral depressions in the template and correspondingly shaped forming jaws in such a way that the wires are first bent to more than 180 degrees with respect to the wire layer on the other side of the template.

[0010] This variant takes into account the fact that the wires are not only plastically deformed when bent around the edge of the template, but also always have an elastic deformation component by which they spring back or which remains in the winding as a type of spring tension. The overbending during re-forming compensates for the elastic deformation component, and the wires can spring back to their ideal position of 180 degrees after the forming jaws are removed. As a rule, the process will stipulate that the template is rotated to an angle at which the wire guide is just not in contact with the template before re-forming, but deviations are possible. Typically, the template is rotated by approximately 175 degrees before re-forming.

[0011] The present invention also relates to a device for winding wave windings from a plurality of wires fed in parallel by means of a wire guide, which initially run perpendicular to the axis of rotation of a flat, sword-shaped template which can be rotated stepwise by means of a drive device, and means for reshaping the winding heads.In accordance with the objective already mentioned above of producing a wave winding of better quality, it is provided that the means for reshaping the winding heads consist of a pair of forming jaws for reshaping a winding head, wherein the pair of forming jaws are held on a movable device which, after interrupting a winding process before reaching a 180 degree rotation, brings the forming jaws into the area of ​​the winding head and there clamps the last produced winding head against the template and reshapes it, and after retracting the wire feed and releasing the pair of forming jaws, removes it again from the rotation area of ​​the template before the drive device completes the rotation process up to 180 degrees, wherein the movements of the drive device, the wire feed and the movable device are coordinated by means of a control device.

[0012] According to the invention, means for reshaping the winding heads are integrated into the device and its operating sequence in the manner described above. Other types of reshaping devices known from the prior art can be eliminated, and the windings produced with a device according to the invention are subject to less stress and are more dimensionally stable, thus allowing for better processing in the subsequent process.

[0013] It is preferably provided that the control device interrupts the winding process before the wire feed comes into contact with the template and the post-forming process of the last produced winding head takes place in a rotational angle position of the template of approximately 175 degrees that the forming jaws are formed on a forming tongs.

[0014] Particularly preferred is an embodiment of the device in which the template has a recess on one or both sides in the area of ​​the winding heads. This recess, in conjunction with mold jaws with a corresponding shape, enables the wire to be bent by more than 180 degrees. The advantages of the overbending of the wires made possible by a device of this type have already been discussed above in connection with the description of a preferred embodiment of the method.

[0015] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the exemplary embodiment described below with reference to the drawings. They show:

[0016] Fig. 1 a) to d) a schematic sequence of a partial winding process according to the prior art Fig. 2 a schematic plan view of an individual wire of a winding head;

[0017] Fig. 3 is a side view of the winding head of Fig. 2 after a conventional partial winding process;

[0018] Fig. 4 a detail of the bending point of the wire;

[0019] Fig. 5 shows a device according to the invention;

[0020] Fig. 6 a) to f) a schematic sequence of the partial winding process according to the invention;

[0021] Fig. 7 is a side view of a preferred embodiment of the winding device;

[0022] Fig. 8 is an enlarged detail view X from Fig. 7.

[0023] Fig. 1 shows the previously conventional sequence of a partial winding process for producing a flat wave winding 20 using a flat, sword-shaped template 10 that is mounted for rotation about a rotation axis 12 and is rotated step by step by a drive device (not shown) to wind a plurality of wires, of which only one wire 14 is shown, onto the template 10. Between the partial winding processes, the wires are axially shifted / deformed so that the wave winding is ultimately strip-shaped. The wires 14 are fed and stabilized by a wire feed 16.

[0024] A partial winding process is carried out by rotating the template 10 by slightly less than 180 degrees, after the wires in front of the template have been laterally offset relative to the wires lying on the template. The center of the inclined transition region created in this way lies in the region of a bending edge 18 of the template 10. The transition region is created by axial displacement (with respect to the longitudinal extent of the template 10) between the wire feed and a clamping device (not shown) provided on the template 10. This is known and can also be implemented accordingly within the scope of the present invention. Starting from this state shown in Fig. 1 a), the template is now rotated counterclockwise as shown, with Fig. 1 b) showing an intermediate position at a rotation angle of 90 degrees. This can be clearly seen in Fig.1 b) the wire feed 16 following the wire, which prevents deformation of the transition area, which is required for the formation of the roof shape of the winding heads (see also Fig. 2).

[0025] Fig. 1 c) shows a state in which the rotation of the template must initially be aborted at approximately 175 degrees, because further rotation would cause the wire feed 16 to collide with the template 10 at a collision point K. Depending on the geometry, the angle may vary. However, a bend of 180 degrees is not possible.

[0026] In a further step, the wire feed 16 must now be retracted (see Fig. 1 d)) before the template can complete half a revolution for this partial winding step (see Fig. 1 e). However, the wires are no longer fixed near the bending edge 18, so they can no longer be plastically deformed. Elastic stresses remain in the wire, which accumulate with increasing winding progress and complicate further processing of the wave winding after removal from the template 10. Furthermore, removing the wire feed 16 can lead to deformation of the winding heads due to frictional forces introduced into the wires.

[0027] Figs. 2 to 4 show the winding head region 20 produced after such a partial winding process. Fig. 2 illustrates the shape of the winding heads with the shape made possible by the transition region and completed by bending around the bending edge 18. From Fig.

[0028] Figure 3 clearly shows the shape the wire would take in a stress-free state. However, since additional windings with winding heads follow, the stresses remain in the wire. Figure 4 illustrates the wire bending in detail. The bend B1 achievable with current practice is shown at approximately 175°, while the theoretical ideal bending state B2 up to 180°, desired for subsequent processes, is shown next to it. An area B3 to be overbent is shown adjacent to this ideal area, which would be necessary to account for springback in the wire.

[0029] Fig. 5 shows a device according to the invention, which, compared to the prior art, is supplemented by a forming tong 22 with two forming jaws 24, 26 that can be moved into the engagement area with the template 10. All other parts in this simple embodiment correspond to the prior art. A device enables the forming tong 22 to be moved between the position shown in Fig. 5, in which reshaping of the previously produced winding heads is possible by pressing the forming jaws 24, 26 together, and a retracted position (see Fig. 6 a), e) and f)), in which the template is freely rotatable during the partial winding processes.

[0030] Fig. 6 shows the steps of the method according to the invention using the device shown in Fig. 5.

[0031] The deviating sequence compared to the prior art is shown in Fig. 6 a), which in principle corresponds to the state according to Fig. 1 c), when the rotation of the template 10 for bending the wires 14 has to be stopped in order to avoid a collision of the wire feed 16 with the template.

[0032] Deviating from the prior art, before the wire feeder 16 is retracted, the forming tongs 22 are brought into engagement with the previously wound wires, and the forming jaws 24, 26 are closed. This reshapes the wires 14, and in particular, the wires 14 are bent further toward the 180-degree bend in the area of ​​the bending edge 18. Only after this reshaping is the wire feeder 16 removed, with the forming jaws 24, 26 remaining closed, so that any frictional forces acting on the wires 14 during the removal of the wire feeder 16 cannot deform the winding heads.

[0033] After removing the wire feed 16, the forming tongs 22 are opened and retracted, whereby the deformation produced in the engagement area of ​​the forming jaws 24, 26 is not visible in the illustration.

[0034] Since the wires 14 always exhibit an elastic deformation component, which, after removal of the forming tools, manifests itself in a springback of the wires or in a tension remaining in the wire, the embodiment of the device shown in Figs. 7 and 8 provides a template 110 which, in the region of the winding heads in the post-forming area, has recesses 30 or clearances which interact with correspondingly shaped forming jaws 124, 126. Since the wires can be bent into the recesses 30, the overall bending angle in the region of the bending edge 18 is more than 180 degrees. This can be referred to as overbending of the wires 14. After removal of the forming jaws 124, 126, the wires can then spring back into the tension-free state with a bending angle of 180 degrees corresponding to the ideal, so that the produced wave winding exhibits less tension overall and can be processed better subsequently.

[0035] All features and advantages arising from the claims and the description, including structural details, spatial arrangements and method steps, can be essential to the invention both individually and in a wide variety of combinations.

[0036] Reference symbol list

[0037] 10, 110 template

[0038] 12 Template rotation axis 14 Wire

[0039] 16 Wire feed

[0040] 18 Bending edge of the template

[0041] 20 winding heads

[0042] 22 mold tongs 24, 124 mold jaw

[0043] 26, 126 Form baking

[0044] 30 recesses / clearances

[0045] 100 Wave winding K Collision point

Claims

A method for forming a wave winding by means of a flat template (10; 110) which is rotatable about its longitudinal axis, wherein a plurality of parallel wires (14) are fed by means of a wire feed (16) perpendicular to the axis of rotation of the template (10; 110), wherein the wires (14) are alternately wound around the template (10; 110) by stepwise rotation thereof and are formed into a wave winding (100) by means of lateral displacement relative to the wires (14) already lying on the template, wherein during the winding of the wires (14) the wire feed (16) follows the wires into the region of the template (10), characterized in that during the winding of the wires (14) the template (10) is first rotated by less than 180 degrees, in an intermediate step the just partially formed winding heads (20) are reshaped by means of forming jaws (24, 26;124, 126), then the wire feed (16) is withdrawn from the area of ​​the template (10) and finally the template (10) is rotated a further 180 degrees for the final shaping of the winding heads (20). Method according to claim 1, characterized in that the forming jaws (24, 26; 124, 126) remain closed until after the wire feed (16) has been removed. Method according to claim 1 or 2, characterized in that the forming jaws (24, 26; 124, 126) are brought into the engagement area with the wires (14) only for the duration of the forming process. Method according to one of the preceding claims, characterized in that the reshaping is carried out by means of a one-sided or two congruent double-sided recesses (30) in the template (10) and correspondingly shaped forming jaws (124;126) is carried out in such a way that the wires (14) are first bent to more than 180 degrees with respect to the wire layer on the other side of the template (10). Method according to one of the preceding claims, characterized in that the template (10) is rotated prior to reshaping to an angle at which the wire guide (16) is just not yet in contact with the template (10).

6. Method according to claim 5, characterized in that the template (10) is rotated by approximately 175 degrees before reshaping.

7. Device for winding wave windings (100) from a plurality of wires (14) fed in parallel by means of a wire feed (16), which initially run perpendicular to the axis of rotation (12) of a flat, sword-shaped template (10) which is rotatable stepwise by means of a drive device and has means for reshaping the winding heads (20), characterized in that the means for reshaping the winding heads (20) consist of a pair of forming jaws (24, 26; 124, 126) for reshaping a winding head (20), wherein the pair of forming jaws (24, 26; 124, 126) are held on a movable device which, after interrupting a winding process before reaching a 180-degree rotation, brings the forming jaws (24, 26; 124, 126) into the area of ​​the winding head (20) and there presses the last-produced winding head against the template (10) is clamped and reshaped, and after retracting the wire feed (16) and releasing the pair of forming jaws (24, 26;124, 126) removes it again from the rotation range of the template (10) before the drive device completes the rotation process to 180 degrees, wherein the movements of the drive device, the wire feed (16) and the movable device are coordinated by means of a control device; 8. Device according to claim 7, characterized in that the control device interrupts the winding process before the wire feed (16) comes into contact with the template (10) and the post-forming process of the last produced winding head (20) takes place in a rotational angle position of the template (10) of approximately 175 degrees.

9. Device according to claim 7 or 8, characterized in that the mold jaws (24, 26; 124, 126) are formed on a molding tong (22).

10. Device according to one of claims 7 to 9, characterized in that the template (10) in the region of the winding heads (20) has a recess (30) on one or both sides, which, in cooperation with forming jaws (124, 126) with a corresponding shape, enables a wire guide bent by more than 180 degrees.